Spinal needles are primarily used to introduce chemicals into, withdraw CSF (cerebral spinal fluid) from, and measure the pressure in the spinal column. Combined spinal-epidural techniques are also prevalent using a needle through needle technique to guide an epidural needle almost as far as the dura mater, then advance the spinal needle into the dura itself. Spinal needles are also used to introduce chemicals into other areas of the body near various nerve endings. Standard procedure entails placing an introducer needle through one of the lumbar spine interspaces, then advancing a spinal needle through the introducer through the ligamentum flavum and the arachnoid. Once the dura mater is reached, CSF appears in the hub, serving as an indication that the spinal needle has been properly placed.
Prior art devices that indicate the flashback of fluids such as blood, are well known. Additionally, at least one flashback indicator system, described in European Patent Application No. 139,872, describes the use of a magnifier element for providing an apparent enhanced visual image of the flashback of the blood as it flows into the hub.
However, the aforementioned devices are perceived to be deficient in several respects. For example, it is a perceived deficiency that the current devices do not sufficiently enhance the flashback of the liquid, such as blood or CSF. By using the invention disclosed herein, the practitioner can more readily determine that proper needle placement has been made than previously achievable.
Additionally, since the amount of CSF fluid lost through the needle is necessarily small to prevent spinal headache, and in order for practitioners to quickly visualize this fluid, needle manufactures have attempted to modify standard needle hubs by reducing the volume inside the hub, protruding the cannula directly into the hub viewing area, and allowing the fluid to be easily viewed by reducing the amount of plastic between the hub inside diameter and the viewer. However, even these constructions have perceived drawbacks some of which are set forth below, and some of which will become apparent after a review of the following disclosure.
Accordingly, because of the need to quickly view the CSF fluid or other fluid, such as blood, it is desired to provide a hub especially designed to rapidly show the fluid by magnifying it, preferably about three (3) times, to the practitioner as soon as it appears from the cannula. The present invention achieves these and other objectives by providing a cylindrical optical magnifier molded directly as a part of the plastic hub in a manner that more quickly and efficiently allows the practitioner to know when the dura mater, or other lining, such as in a blood vessel, has been punctured.
Therefore, it is an object of the present invention to provide an improved magnifying hub.
It is another object of the present invention to provide an improved cylindrical CSF magnifier molded directly as a part of a spinal needle hub to magnify CSF fluid, preferably about three (3) times size.
It is another object of the invention to frost particular surfaces of the hub in order to improve the contrast between the magnifier and the hub surfaces to thus facilitate the viewing of the contents of the flashback chamber of the hub.
It is yet another object of the present invention to coordinate the shape of the magnifier and the internal flashback chamber to further reduce or eliminate any distortion of the contents of the chamber.
It is still another object to provide an improved magnifier hub that can be easily manufactured.
It is another object of the present invention to reduce or eliminate distortion of the magnified fluid, achievable by coordinating the shape of the flashback chamber and the magnifier.
It is yet another object of the present invention to provide a magnifying hub that achieves all of the foregoing and below-mentioned objectives and advantages while remaining sufficiently small in size.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the disclosure hereinafter set forth, and the scope of the invention will be indicated in the claims.
Generally speaking, the present invention comprises an arrangement used in connection with the withdrawal of cerebral spinal fluid (CSF) from a spinal column. In a preferred embodiment, the arrangement comprises a hub having a chamber therein for receiving CSF, a cannula coupled to the hub to permit communication of CSF with the hub and dimensioned to permit withdrawal of the CSF from a spinal column, wherein the hub includes walls forming an opening therebetween, and wherein a arcuately shaped magnifier is disposed within the opening. The magnifier preferably includes edges that extend below the top surface of the walls of the hub such that at least a portion of the curved outer surface of the magnifier extends below the top surface of the walls of the hub so as to allow the magnifier to be positioned in close proximity to the chamber to improve magnification of the CSF as it enters the chamber and decrease the recognition time from when the CSF first enters the chamber of the hub.
In yet a preferred construction, the top surface of at least one of the walls around the opening in which the magnifier is disposed is frosted to increase the contrast between the magnified area and the hub. Further the magnifier is preferably dimensioned to magnify the CSF fluid about three (3) times. The hub may include finger grips located on adjacent sides of the hub for facilitating the positioning of the hub during cannula placement in a spinal column. An integrally molded bevel orientation indicator may be provided on the cannula hub for facilitating the proper alignment of the cannula.
Preferably, a portion of the curved outer surface of the magnifier extends above the top surface of the walls of the hub on the side of the hub through which the opening is formed to both improve magnification while maintaining the small size of the hub. Further, both the magnifier and the chamber of the hub are cylindrical in shape to eliminate or reduce magnification distortion.
In accordance with the present invention, a flashback indicator is also provided wherein the chamber therein is dimensioned to receiving a bodily fluid, such as blood or CSF. Similarly, the cannula is coupled to the hub to permit communication of the bodily fluid with the hub. Likewise, the hub includes walls forming an opening therebetween for the positioning of an arcuately shaped magnifier to be disposed therein. The magnifier includes edges that extend below the top surface of the walls of the hub such that at least a portion of the curved outer surface of the magnifier extends below the top surface of the walls of the hub to permit the magnifier to be positioned in close proximity to the chamber to improve magnification of the bodily fluid as it enters the chamber and decrease the recognition time from when the bodily fluid first enters the chamber of the hub.
The present invention also discloses and claims a hub for use in such a flashback arrangement.